I used to live in a victorian terrace house, just two bricks width separation between neighbouring house rooms. My widow neighbour of 63 years old used to masturbate with a vibrator quite frequently. She slept in bedroom next to my own bedroom and probably used to masturbate three times a week and occasionally several times in one night. I couldn't here any sighs or moans but the rise and fall sounds of the motor was unmistakable.